1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device and, more specifically, is preferably applied to the formation of a source and a drain in a MOS transistor of a generation having a gate length of less than 0.1 μm.
2. Description of the Related Art
In recent years, the laser annealing technique is expected as thermal process of the next generation, replacing rapid lamp heating. This technique, nonequilibrium thermal process which is a melting and re-crystallization process in a very short period of time of several nanoseconds, has advantages in its capability of obtaining high electrical activity exceeding the solubility limit of impurities in a semiconductor which is normally limited by temperature and, further, of obtaining a sharp impurity profile. Therefore, this technique enables the formation of a source and a drain having a low contact resistance and shallower and sharper impurity extension regions.
However, the sharp impurity extension obtained by the laser annealing has a disadvantage in that the impurity extension region in the vicinity of a gate electrode which is a mask during ion implantation is strictly defined because the impurity profile is too sharp, which inversely increases its parasitic resistance.
As described above, the use of the laser annealing method provides this sharp impurity profile due to the activating process in a very short period of time which greatly contributes to a reduction in the contact resistance and so on, but conversely presents a serious problem in the increase in parasitic resistance.